Lost Register key

hi
I have a customer that buy original Node but he lost pack of node and his register key
he even dont remind that what kind of emails use for register(UNTAUGHT customer)he have only one original cd of node
now,he come to me and he want help of me!!
however he remind your name an he guess your email
name: <removed>
last name: <removed>
guess email: <removed>
please help me and my customer
note:i call agency of node in my country but they say:we cant help you
thx a lot

hi
thx for your answer
I enter customers email(he guess that enter this email during register) but dont receive any email of node for he
UNFORTUNATELY node site(http://www.eset.com/us/support/lost-license) accept any email and dont say that 'this email register and Your username and password will be emailed to you shortly' or 'this email dont register'
now what i can work?
one quetion:'if my customer install node,can node group find any information about License details with connect to his node or with use path program'
thx a lot

Without knowing what system that ESET office uses to keep and organize their customer records, it's hard to tell what information might help them locate the customer's record however, the following information would certainly help:

Full name

Email address (listing all known email addresses they use helps a lot)

Serial number/activation key (found inside CD case or on the back of the CD sleeve)

Phone number

Street address

It may also help if the customer themselves contact the ESET office for assistance as that office may not be willing to give license information to anyone who is not the actual customer.